Happy Valentine’s Day!
Can you spot all three marine organisms in this picture?
The heart in our Valentine’s Day photo is actually a uniquely-shaped vase sponge. These sponges are usually found on coral reefs and can be pink, purple, or even fluorescent blue. As members of the Porifera phylum, these organisms lack true tissue and organs but get their nutrients by feeding on the suspended particles in the water flowing through their body cavities.
The organism on the left side of the vase sponge is a brittle star, relative of the starfish. Brittle stars have five limbs radiating out of a main body disk where all of the internal organs are concentrated. If a limb is lost or shed to avoid predation, it can readily be regenerated, similar to the tails of some lizards.
The organism on the right side of the vase sponge is actually an arrow crab, not a spider. These invertebrates are nocturnal and territorial. They have eight spider-like legs radiating out of their body and can grow up to 10 cm across.